Manchester United manager Jose Mourinho leaves the pitch after the final whistle in Sunday's defeat to Manchester City at Old Trafford. Photo: Martin Rickett / PA

MANCHESTER - Manchester United and Manchester City players were involved in an ugly tunnel fracas as tempers boiled over following Sunday's derby clash.

As City celebrated their 2-1 win at Old Trafford, United manager Jose Mourinho allegedly had water squirted at him and was hit on the head by an empty plastic bottle while a melee ensued involving more than 20 players and staff.

Mourinho and his disappointed players had demanded that City players show "more respect" when their celebrations seemingly got out of hand.

The United boss had been heading from the home dressing room to do his post-match press conference when he walked past City’s dressing room and, when he made his feelings known, he was confronted by City goalkeeper Ederson.

United’s players were enraged by the perceived gloating of City players and followed Mourinho into the tunnel area which

sparked the skirmishes between both sets of players.

It was reported that some players tried to swing punches at each other while police, who were already present in the corridor outside the referees’ room, looked on in disbelief.

Old Trafford security staff were forced to to disperse the brawl as United players blamed their City counterparts for "rubbing their noses in defeat" by "whooping and cheering".

After tempers were eventually calmed, police remained present outside the dressing-rooms.

A United insider said: "Nobody minds celebrating but the lads deemed that excessive."

City were unavailable for comment on Sunday night.

Mourinho being struck on the head by a plastic bottle was reminiscent of Sir Alex Ferguson being hit by pizza during the infamous "Battle of the Buffet" at Old Trafford in October 2004.

Cesc Fabregas recently confessed he threw the pizza at Ferguson after United had beaten Arsenal 2-0 to end their 49-game unbeaten Premier League run.